What are lyophilized reagents
Lyophilization, or freeze-drying, is a preservation process that removes water from material in order to further shelf life and stability.
Methods of freeze-drying, especially for food preservation, have been employed for thousands of years. Ancient South Americans residing in the Andes took advantage of the freezing mountainous temperatures and low atmospheric pressure to preserve potato crops for long periods. Monks living in feudal Japan used a similar process to preserve tofu.
Freeze-drying, or lyophilization, is based on sublimation (transition of a solid into a gas). Since the process is dependent on a phase change, temperature and atmospheric pressure play an essential role in governing the phase change. In order for sublimation to occur, temperature and atmospheric pressure have to reach a certain threshold. The phase change diagram below illustrates the relationships between the phases, temperature and atmospheric pressure.
While lyophilization is still used for food preservation, it is also used for reagents and pharmaceuticals. The exploration of lyophilizing biological samples began in the 1930s with plasma. Now, researchers use it for proteins, viruses, microbes and chemicals. And when lyophilized products are ready for use, they can be solubilized with an aqueous solution or solvent.
Lyophilized reagents, therefore, are reagents that have been freeze-dried for longer stability and storage. Rather than remaining in an aqueous solution, these products are in powder form, which can be solubilized for later use.
What are the benefits of lyophilized proteinase K?
Benefits of ordering lyophilized reagents such as proteinase K include high stability, long shelf life and inexpensive shipping. Lyophiliziation also does not reduce the activity of proteinase K.
Lyophilized proteinase K is stable enough to ship at ambient temperatures. Therefore rather than paying extra for a blue ice shipment, the domestic shipping of proteinase K qualifies for inexpensive ground shipping.
Lyophilized proteinase K, when properly stored, remains stable for a very long time.
Another benefit to lyophilized proteinase K is the overall cost of the powered product versus solution. A 100 mg pack of proteinase K currently will make 5 milliliters of a 20 mg/ml stock solution (see our stock solution calculator to convert grams into solution). The powder version ultimately gives you more product per milliliter than the 2-milliliter bottle of 20 mg/ml proteinase K at a lower unit cost.
What are the benefits of proteinase K solution
With all of the benefits of lyophilized proteinase K, why would you consider ordering solution? It boils down to convenience. And there is a lot of convenience when it comes to the ready-made solution.
The first is time-savings. Proteinase K solution is ready to go, which means there is no time spent solubilizing your proteinase K powder.
Next, there is less risk of contaminating your proteinase K, which would threaten your DNA or RNA samples.
Finally, proteinase K solution offers consistent formulation and activity due to batch production.
Should I choose proteinase K powder or solution?
To determine which product best satisfies your needs, all you have to do is think about your needs. In terms of cost, consistency and convenience, what is most necessary for your experiment?
This table summarizes the benefits of each product so you can easily come to a conclusion.
Please note that ready-made proteinase K is still very affordable, but if you're looking for value, savings and ambient shipping, proteinase K powder might be the better option.
Harris, T. (2020, January 27). How Freeze-Drying Works. Retrieved April 1, 2020, from https://science.howstuffworks.com/innovation/edible-innovations/freeze-drying2.htm
Wang, W. (2000). Lyophilization and development of solid protein pharmaceuticals. International journal of pharmaceutics, 203(1-2), 1-60.